We’ve put together a list of some of the most frequently asked questions our customers have asked us over the years. Our hope is they shed some light on a widely used but not always well understood product.
What is an oxygen absorber?
An oxygen absorber or oxygen scavenger is a porous sachet that removes the oxygen from the atmosphere. The absence of oxygen prolongs the shelf life of food products. They are commonly used in food packaging to:
- help retain the original flavour, colour, smell and texture,
- inhibit oils in foods from becoming rancid, and
- prevent the growth of oxygen-loving microorganisms such as bacteria, mould and fungi which leads to food spoiling.
What does an oxygen absorber do?
Oxygen absorbers use the available moisture in the food and air to cause the iron particles in the sachet to ‘rust’, thereby removing the available oxygen in the air. The food packaging is then left with a higher concentration of nitrogen, which are better conditions for a longer shelf life. Trapping the oxygen usually generates a small amount of heat.
When would I typically use oxygen absorbers?
Oxygen absorbers are used in many products, including but not limited to:
- Pasta and noodles
- Rice, grain, pasta, seeds & nuts
- Dried fruits & vegetables
- Spices, seasonings & herbs
- Coffee, tea, cocoa & confectionary
- Processed, smoked & cured meats
- Bakery goods such as flat breads, cakes, pastries
- Pharmaceuticals, vitamins & herbal medicines
- Diagnostic kits & devices
- Pet foods & Birdseed
- Stationery and artwork preservation
How do I know if my oxygen absorber is working?
A new oxygen absorber will have a loose powdered feel when pinched. It should feel free of clumps and may feel warm (a by-product of the absorber working in a moist environment). Spent (or expired) absorbers can feel hard or clumpy to touch.
How long does it take for them to work?
Oxygen absorbers once exposed to the atmosphere begin to get to work immediately. That is why, we suggest that unused oxygen absorbers should be resealed within 15 minutes to ensure the integrity of the product is maintained.
How can I be assured that the oxygen absorbers I received are new and ready to use?
We understand that Protection Experts Australia customers should feel confident they are receiving the best quality products. And that is why all our oxygen absorbers are packaged with a quality check, called the ‘eye’.
The indicating eye is packaged with the oxygen absorbers and will appear pink showing that the package is sealed and oxygen-free. Should the eye appear purple, this indicates that oxygen has penetrated the packaging through possibly a puncture or poor seal and the oxygen absorbers have been compromised. In this instance, we ask that you contact our office immediately so that the problem can be rectified.
I don’t need to use them all, how can I store my oxygen absorbers, so they last?
Store oxygen absorbers at room temperature (5C to 30C), away from direct sunlight. They should be stored in their sealed package or a glass jar with a gasketed lid. Select the smallest glass jar possible to minimise the oxygen the absorbers will remove from the jar. Oxygen absorbers in a well-sealed container will cause the lid to pop down.
The shelf life of an oxygen absorber is up to 18 months.
How long will it take an oxygen absorber to remove all the oxygen from my sealed bag/container?
How quickly oxygen absorbers remove oxygen from the atmosphere will depend on the conditions. In dryer climates, it may take up to a week for absorbers to fully activate. Warmer, humid climates however accelerate the process and may take only 48 hours for the same result.
I’m using oxygen absorbers, why aren’t my bags getting hard?
Oxygen Absorbers trap oxygen. Given that air comprises 20% oxygen and 80% nitrogen, the absorber will only be removing the 20% of the atmosphere that is oxygen. The volume of nitrogen remaining will mean your bag will not deflate to the extent of the bag becoming hard or rigid.
How many oxygen absorbers do I need?
The factors to consider when calculating how many oxygen absorbers you require are:
- The volume of the sealed package
- The volume occupied by the food product.
The oxygen absorber calculation isolates the volume of the food packaging void – sealed package volume less food weight – multiplied by 20%. The factor of 20% reflects that our atmosphere comprises 20% oxygen and 80% nitrogen.
For those who like the numbers, the formula is:
And for those who prefer a shortcut (who doesn’t), check out our online Oxygen Absorber Calculator to find out how many you will need at the click of a button.